Heart Anatomy Notes PDF

Heart A. The heart (A fist size muscular organ & the Key organ & the circulatory system) a. Location & orientation within the thorax: 1. Apex- narrow and inferior 2. Base- broad and superior b. Coverings (2 primary layers) 1. Fibrous- Pericardium (outer la...

Heart A. The heart (A fist size muscular organ & the Key organ & the circulatory system) a. Location & orientation within the thorax: 1. Apex- narrow and inferior 2. Base- broad and superior b. Coverings (2 primary layers) 1. Fibrous- Pericardium (outer layer) A. strong layer of dense C.T. B. Helps hold heart in place & keeps it from overfilling w/ blood c. Serous pericardium 1. parietal layer- adheres to the inner ;ayer of the fibrous pericardium 2. Pericardial cavity- Space between parietal & visceral layers A. Fluid which helps reduce friction 3. visceral layer - also called epicardium B. layers of the heart wall (3 layers) a. Epicardium- outer layer of heart b. myocardium- consists of cardiac muscle cells (middle layer) c. Endocardium (inner layer) 1. A sheet of simple squamous epithelium A. thin layer of C.T d. Flow of blood through hearty (4 valves in the heart) 1. Vena Cavae 2. Right atrium (both atria) 3. Tricuspid valve 4. right ventricle 5. Pulmonary Semilunar valve 6. Pulmonary trunk/artery( taking away blood from heart CO2) 7. Pulmonary arteries 8. Pulmonary capillaries ( bringing back blood with O2) 9. Pulmonary Veins 10. Left Atrium 11. Mitral Valve 12. Left Ventricle 13. Aortic valve 14. Aorta e. Conduction system 1. Conducting system( Pathway which electrical current travels through the heart) A. Sinoatrial node (pace maker of heart) B. Atrioventricular node: a. Located in the inferior part of interatrial septum f. Blood supply to the heart( the first branches off aorta: LT & RT coronary arteries) 1. Left coronary artery 2. Right coronary artery 3. Coronary Sinus C. Blood Vessels: The science of B.v. "Angiology" ( B.V. are organs) a. Structure of blood vessels 1. Lumen A. Tunica Intima or Tunica Interna (a coat??) a. Endothelium- Simple squamous epithelium  b. Subendothelial layer 1. loose C.T. 2. Tunica Media: Predominately made of Elastic Fiber & Some smooth only found in the middle layer. A. Thickest layer of the three layers B. Thicker in arteries than veins 3. Tunica Externa or Tunica Adventita A. Layer of C.T. w/ Lots of collagen (protect the artery and give it strengthen) & Elastic Fibers b. Types of Blood vessels 1. Arteries carry blood away from the heart A. Elastic (conducting) Arteries: a. Largest arteries near the heart; aorta & its major branches 1. more elastin in these than in other arteries 2. Muscular Artery (Distributing arteries) A. Tunic media in these is thicker than in other arteries B. Majority of arteries are muscular C. More muscles and less elastic tissue in their walls 3. Arterioles A. smallest arteries B. only contain one or two layers of smooth muscle cells 4. Capillaries A. General structures a. smallest blood vessels composed of a single layer of endothelial cells surrounded by a basement membrane B. Capillary beds: a. run throughout all the body's tissues C. permeability a. Intercellular clefts 1. Gaps of unjoined membrane 2. Most exchanged of materials occurs through these openings b. Pericytes: 1. Thought to pick up substances from leaking blood vessels c. Types of capillaries (carry away from the heart) 1. Fenestrated capillary A. Have fenestration (pores) spanning epithelial cells. B. Found only where there are high rates of exchange of small molecules 2. Continuous A. No fenestrations B. Most capillaries are of this type 3. Sinusoids (high permeability) A. wide, leaky capillaries B. found where materials such as proteins and cells are exchanged as in bone marrow & spleen. D. Veins- Carry blood toward the heart a. General structure 1. walls are thinner than arteries and also contain less elastic tissue 2. Tunica externa- Thicker than the tunica media 3. Lumen is larger than in arteries and hold about 65% of body's blood  b. Venules (Smallest Veins) Lymphatic & Immune system A. Functions of lymphatic system a. return lymph back into the bloodstream b. Return leaked proteins into the bloodstream c. carry absorbed fat from the intestine to the blood. B. Flow chart a. Lymph (start) b. Lymphatic capillaries c. lymphatic (collecting vessels) d. Lymph Nodes e. Lymphatic trunk f. Collecting ducts (the largest type of lymphatic vessels) g. Deposited in the internal jugular vein & subclavian vein C. Lymph nodes (inside are macrophages and lymphocytes) a. clean lymph of pathogens b. lymph is a tissue fluid 1. consist of water mostly, proteins, sugars, fat & Ions c. Not found in brain d. Bean shaped organs situated along lymphatic collecting vessels e. about 500 lymph nodes in the human bodies